This invention relates to cylindrical, metallized film wound capacitors and, more particularly, to such capacitors and the method of making the same which provide a protective interrupter device incorporated in the construction.
Very large size capacitors have been made from foils separated by a dielectric layer and characteristically packaged in an oil filled can. The oil increases the dielectric constant of the dielectric layer to increase the capacitance of the can type capacitor. In such capacitors the foil is thick enough such that any overload or malfunction of the capacitor would tend to short the layers of foil which would probably short a circuit breaker or fuse protecting the power supply which supplies the power across the capacitor. In view of the toxic nature of gases which may be generated from a faulty oil filled can type capacitor and the desirability of eliminating combustible fluid from the capacitor, dry type can packaged capacitors wound from metallized films have been produced. The metallized layers which form the plates of the capacitors are on the order of one millionth (0.000001) of an inch thick. Such metallized capacitors have a tendency under certain conditions to exhibit failure modes involving heavy clearings which lead to internal sparking and possibly combustion. Accordingly, the metallized capacitors do not tend to short as foil and film capacitors would. The metallized layer is so thin that it tends to vaporize and continues to do so while voltage is being applied. Accordingly, under such circumstances burning and an explosion could take piece.
Accordingly, it is an object of this invention to provide a metallized capacitor with a protective interrupter device incorporated therein to disconnect the power supply in the event of an internal fault.
A further object of this invention is to provide a new and improved metallized capacitor with a protective interrupter device incorporated in its construction whereby potential injury from fire or explosion is avoided.
Still another object of this invention is to provide a protective device for a metallized capacitor which is simple in construction and may be readily incorporated in a capacitor.